What is a Dinosaur Mummy?

The big photo above is Leonardo. It is easy to see that he looks like he laid
down and died. Keep in mind that
Leonardo became a mummy before he became a fossil. So, like the famous mummies of humans that
you see from places like Egypt,
Leonardo pretty much shriveled up, his skin sinking in tightly around his bones
and tendons. That’s why he looks all
scrunched up.

Almost all the fossils of dinosaurs that we find are just
bones, or the imprints of bones. There
are several reasons for that. First, dinosaurs
were mostly meat, and the world is full of things that like to eat meat. These meat eaters can be other dinosaurs,
small mammals, insects and on a really small scale, bacteria. The chances for anything except bone to
survive all these flesh eating critters is very slim. And some of these critters would even eat the
bone. Anytime there was a dead dinosaur
lying around, there was a very big chance that something would eat it.

Just to become a fossil is very rare. If all the dinosaurs that ever lived had
become fossils, we would be up to our eyeballs in dinosaur bones. It took very special conditions for a
dinosaur to become a fossil. What
usually happens to make a fossil is that the bones of the dead dinosaur end up in a stream or
river where they wash into a bend in the river.
Then, some kind of big storm will put a lot of mud or sand into the
water and when it reached the bend in the river, the mud or sand collects and
covers the fossil. The next step is that
the water level goes down long enough for the fossil to stay buried for a long
time, usually several hundred years or longer.
During this time, water will very slowly seep through the bones and deposit
minerals. This process is called
permineralization and it is what turns a bone into a fossil. Sometimes all the real bone goes away, and in
some cases the real bone cells can still be found, surrounded by the mineral
deposits.

You can see that it isn’t easy for a dinosaur to become a
fossil. A dinosaur that died on land
would find it nearly impossible to become a fossil as there would be no way for
it to be buried. Burial is necessary to
become a fossil. The exception to this
are some of the rare fossils from Mongolia
where sandstorms buried the dinosaurs on dry land.

Take a look at the photo to the left. That is a picture of what, until
Leonardo was found, people thought was a great example of a dinosaur mummy. It is at the wonderful American
Museum of Natural History and was
found in 1907 by Charles Sternberg.
Until Leonardo was found, it was inconceivable to most scientists that
the perfect conditions to create a fossil like Leonardo could exist. For so much skin to be preserved, and for his
body to be intact, with no openings until tens of millions of years after his
death presented the research team with both tremendous opportunities and some
very big obstacles.